Fullbacks:
Mentality normal but on the defensive side
I have them pushing up often, but in gameplay I'm not really suffering goals on the break down the wing so it does't seem to be the issue
I have them pressuring the whole field (first setting after own field) with man marking and no tight marking

Centrebacks:
Mentality normal but on the defensive side
I have them pressuring own field (first setting back from whole field) with man marking and tight marking

Defensive midfelders (use two):
Mentality normal but on the defensive side
I have them pushing sometimes but without dribbling so they don't get caught out much
I have them pressuring own field (first setting back from whole field) with man marking and tight marking

All these players are with tackling at normal. Used to have the defensive midfielders with a hard tackling but had some disciplinary issues.

What I tend to verify is 3 main things:
1. I tend to suffer a few stupid goals - bad backpasses, balls that fall to forwards after hitting several defenders, and the such.
2. Although I have tight marking, my defensive midfielders give to much space to opposition central midfielder that then puts a through ball to a forward
3. But mainly, my fullback just don't tackle. Often, opposition wingers dribble down the wing with my fullback in front of them but he doesn't tackle. They get to the byline and cross to a forward head in or something of the sort.

Please help!!! I have tweaked the settings above with not much success in altering what I refer.

These are the same problems a lot of people, me included, have been experiencing... I think it's a known ME issue. I hope it'll be fixed soon! I wish I could be more help, but nothing I do either seems to work.

Thus far, the best method seems to be specific marking them with either a winger, an AM or an FC, depending on which is the most logical for your formation. This encourages your player to get behind the dribbler before he gets up to speed, which generally stops the dribble before he sets off. Although it does knock on to some unusual deep marking patterns, which might slightly handicap your ability to counter attack, it does significantly reduce the number of dribbles and provides defensive stability.

I've not tried specific-marking an FC super-dribbler, but doing that with an MC or DMC should produce similar results.